The present invention relates to a fluorine-containing resin composition which can reduce an amount of hydrofluoric acid released from a fluorine-containing resin and inhibits corrosiveness.
It is well known that hydrofluoric acid is released from a fluorine-containing resin and various materials such as metals are subject to deterioration and corrosion due to the released hydrofluoric acid. Therefore expensive corrosion resistant materials such as Hastelloy and Inconel must be used on a molding machine for fluorine-containing resins (especially portions contacting a polymer such as a metallic mold, cylinder and screw), thereby resulting in economical disadvantage.
Such hydrofluoric acid is generated due to decomposition of an unstable end of a fluorine-containing resin, decomposition of an unstable portion such as a head to head bond in a trunk chain of hexafluoropropylene or a de-HF reaction of a vinylidene fluoride portion.
For inhibiting release of hydrofluoric acid, there are proposed a method of decreasing the number of unstable ends, thus reducing hydrofluoric acid releasing sources and a method of applying a shearing force when extruding for pelletizing to previously eliminate unstable portions in a trunk chain (e.g. JP46-23245B, JP 60-171110).
However, in any of the above-mentioned methods, there still remains a problem that special steps are necessary and cost is high.